unable to connect to firebase variant.getMergeResources() error

Question

I am trying to add firebase to my app but when I add apply plugin: 'com.google.gms.google-services' and sync, I get an error

i have updated both android studio and gradle to their latest versions

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.pluralsite.tabianconsulting"
        minSdkVersion 16
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation 'com.google.firebase:firebase-core:17.0.1'
}
apply plugin: 'com.google.gms.google-services'

i expect the build to finish smoothly but instead this error pops up

WARNING: API 'variant.getMergeResources()' is obsolete and has been replaced with 'variant.getMergeResourcesProvider()'. It will be removed at the end of 2019. For more information, see https://d.android.com/r/tools/task-configuration-avoidance. To determine what is calling variant.getMergeResources(), use -Pandroid.debug.obsoleteApi=true on the command line to display more information. Affected Modules: app